Heater



July 21, I925. 1,547,156

A. J. LOEPSINGER HEATER Filed March 6, 1920 'IIIIII/nh 7? INVE NTORATTORNEYS Patented July 21, 1925.

UNITED STATES ALBERT J. LOEPSINGER, F EDGEWOOD,

RHODE ISLAND, ASSIGNOB TO GENERAL FIRE EXTINGUISHER COMPANY, OFPROVIDENCE, BHQDE ISLAND, A CORPORA- TION OF NEW YORK.

HEATER.

Application filed March 6, 1920. Serial No. 363,762.

To aZZwhom it may concern:

Be it known that I, ALBERT J. LOEPSINGER, a citizen. of the UnitedStates, residing at Edgewood, in the county of Providence and State ofRhode Island, have invented certain new and useful Improvements inHeaters, of which the following is a specification. This inventionrelates to improvements in heaters.

method and apparatus for utilizing products of combustion, or other hightempera ture gases, for special purposes, such as drying or evaporating,or for general heating, where the direct application of the hightemperature to the heating or radiating apparatus is objectionable. Forindustrial uses requiring radiation from temperatures higher than thosesafely or easily attained with steam, the gaseous products which comefrom combustion of gas, oil or other fuel offer advantages ofconvenience and of economy. As compared with use of heated oil as adistributing medium, for example, they avoid losses sustained intransferring the heat from one medium to another, and

also avoid the danger of the pipes becoming clogged by carbonization,and the hazard of escape of the hot liquid. The initial temperature ofproducts of combustion is so high, however, that there has been no knownway, so far as I am aware, to produce a reasonably uniform heattherefrom through any considerable length of piping. Attempts toovercome. this objection by mixing a cooler gaseous medium with theproducts of combustion are unsatisfactory, one reason being that thispromptly reduces the high temperature which it is desired to maintain.The present invention relates particularly to a method and apparatus formaintaining high temperature of the products of combustion, for aconsiderable distance through thepipe, the loss of heat therefrom beingbut slow, accompanied, however, by a moderate temperature oft'he pipeitself, predetermined, as high as desired, and having the notablecharacteristic of approximate uniformity throughout th pipe length. Theinvention provides a process and apparatus by which these gases, andeven the flame, pass into a pipe which has no part overheated by them.This is accomplish by providing a More particularly it relates to atubular container, preferably an ordinary iron pipe such as is used inradiators, into which the highly heated gases are introduced in suchmanner that they are kept from direct contact with the metal of thepipe, being separated by a difierentially moving, and preferably a morerapidly moving, envelope or film of a cooler medium, such as air, whichacts as aneat insulator or retardant. The envelope maintains itsposition next the wall of the pipe, seemingly by virtue of the momentumand direc tion of particles moving therein, and keeps itself separatefrom the core of highly heated gases without mixture, for thesamecauses. It can be imagined that a particle of the latter, essayingto'enter the envelope by expansion, after the manner of a gas, whichentry if effected would result in a mixture being made, finds itselfpromptly knocked back, as it were, by encountering some one or moreswiftly moving particles in the envelope before it has time to penetratebetween said particles as it might do if the envelope were moving withequal speed with it. The air envelope being put in through an annularnozzle surrounding the place where the heat carrying gases enter, theexterior temperature of the pipe is found to approximate uniformity fora considerable distance. For practical purposes, it is customary tobuild head radiation coils of successive lengths of straight pipesjoined by return bends. In such cases, it is sometimes desirable toinstall at the bend a fitting which has an annular nozzle to form afreshthe inslulating envelope by the entrance of mor air on account of theenvelope that protected the previous length having become more or lessbroken up by partial mixture with the heated gases at the return bend.

No particular gas to constitute the envelope, and no particular speed,appear necessary to successful operation; but it is generally mostconvenient and best to use air for the envelope and to move it muchfaster than the heated contents which it surrounds. The heat carryinggas that is to be thus insulated from the pipe in such manner as to actas a reservoir of heat, and to part with its heat only slowly, does notnecessarily originate from combustion, nor, if it does, need it proceedimmediatelyfrom the flame into the pipe. The entering envelope tends tohave an injector action, as is particularly observable in case the flameprojects into the tube, when it can be seen drawn out in bottle neckstyle. A suction fan may be used at the discharge end to draw the flameand the gaseous envelope together through the tube, this being useful inthe case of an unusually long coil. The invention may obviously beapplied in many ways, and with various apparatus. It is intended thatthe patent shall cover, by suitable expression in the appended claims,whatever features of patentable novelty exist in the apparatus andmethod or process herein disclosed.

The accompanying drawing illustrates an embodiment of apparatus and amethod of practicing the invention, the single figure being arepresentation in elevation, in medial section, of fragments of a coilof pip ng.

Referring to the drawing: 10 indicates a stretch of pipe which may be,for example, ten or twelve feet long, at the beginning of which is acast iron fitting 11 having an axial funnel 12 through Which theproducts of combustion of a flame 13 may enter, while around this funnel12 is an annular nozzle 14 discharging from an annular chamber 15 towhich air or other relatively cool medium is supplied through a pipe 16and valve 17 under pressure which may, for example, be five or sixpounds per square inch. At the further end of the pipe 10, or at the endof some subsequent length of pipe, where there is to be a deflection ofthe course of the heated gases is a fitting 21 which, as illustrated,makes 180 turn, called a return bend from the pipe 10 at its fulldiameter and reduces into a funnel 22 around which is a chamber 25 andannular nozzle 24 for a fresh supply of enveloping air under pressure,both of which lead into a length of pipe 20 parallel to the length 10.Air is supplied to the chamber 25 through a pipe 26 and valve 27 whichmay in all respects be duplicates of the pipe and valve 16 and 17, andmay discharge air at the same pressure. A continuation of thisarrangement as far as desired, with repeated pipe lengths and deflectingand reenveloping fittings, complete the heater, the contents of whichare finally discharged as may be desired.

In apparatus thus constituted, it has been found that, working with agas flame from a 1" Meeker burner, operating in atmos phere and with apressure of air for the annular nozzle of five or six pounds per squareinch, and with a 2 pipe and with dimensions of fittings approximately asillustrated, the pipe temperature approximates uniformity throughout itswhole straightaway length which is conveniently twelve feet or so. Thisis true whether the pipe be vertical, or be horizontal, which isgenerally preferable. Without the method and apparatus thus describedthe iron piping gets red hot near the burner, while with it thetemperature may be, for example, about 200throughout its length. Thiscondition of uniform temperature will continue around deflections andbends, but not so perfectly. Return bends may be used according to needsand preferences, either of the ordinary simple style, or bends involvingthe re-application of the method set forth, as shown in the upper partof the drawing. Obviously if it were desired such envelopere-establishing nozzles could be in serted in a long straight length.

lVith such apparatus, the total heat of the combustion may be maintainedas in an at tenuated reservoir, from which it gradually escapes at amoderate and useful tempera-- ture. The heat is carried in the centralcurrent, comprising products of combustion and such air as may becomemingled therewith from time to time from the moving envelope. Itprobably passes thence through the envelope by a process akin toradiation, or, if it be by convection, it is only by convectionresulting from movement of particles of .the enveloping medium withinthe mass of such particles which constitute the envelope. In eitherevent it passes but slowly, and the envelope acts as an insulator orretardant conserving the heat of the medium which it surrounds.Conduction and radiation, which proceed promptly of all heat thatreaches the iron wall of the pipe, keep down the temperature of theenvelope. Mean while, the envelope itself does not accumulate heatexcessively for it is continually moving on, and that which has becomeheated to the predetermined degree ultimately removes itself. As thetemperature of the movable screen in the middle of the pipe graduallydiminishes, the later stages of the envelope may be thinner; and thepiping and fittings may be designed with this in mind.

Although the best results are attained with the envelope definitelysurpassing the central current in velocity, experiment has shown thatthere is some benefit in having the air introduced at a slower speedthan the speed of said heated products of combustion.

I claim as my invention 1. In the art of heating, the introduction intoa conduit of a stream of highly heated gases accompanied by theintroduction of an envelope of cooler gases, the gases in said streamand envelope flowing substantially unmixed within the conduit whereby ahigh temperature of said heated gases is maintained to a distance in theconduit.

2. In the art of heating, the provision of a stream of highly heatedgases and the surrounding of it with an envelope of cooler gases movingparallel to it and more rapidly than it, whereby said heated gases aremaintained segregated in a stream for a considerable distance, withinthe said envelope, thereby maintaining a high temperature.

3. A method of retarding distribution of heat from gases, comprising theformation of the heated gases in a stream; the formation of an envelopeof cooler gases sur rounding them, and moving more rapidly, and theconstraining of the said envelope against lateral outward expansion, bysur rounding it with a solid wall, as a pipe, whereby the diffusion ofparticles of the said heated gases toward the pipe, with consequent lossof heat thereto, is retarded.

4. In the art of heating, the introduction to a conduit, having heatconducting and radiating walls, of a stream of heated gases and theco-incident projection into the conduit, by a source of energyindependent of the said stream, of an annular stream of cooler gasesmoving more rapidly than and surrounding the first mentioned stream.

5. The art of transmitting a highly heated gases medium through aconduit with but slow and gradual loss of heat en route, comprising theintroduction and segregation of said medium in the middle of theconduit; the introduction and segregation of a hollow stream of coolergases movlng through the conduit between it and said medium, the saidmedium being at its core; and the maintaining of said streamsrespectively, the one as a core stream and the other as the walls of atubular container of the core stream, substantially without diffusion ofgases of the core stream into the gases of the hollow stream around it.

6. The art of maintaining a radiating surface at approximated uniformityof temperature, with heat supplied from a cloosely adjacent highlyheated gaseous medium, comprising the provision of an intervening coolergaseous medium, and the placing of both mediums in motion parallel tothe said surface, the cooler moving the more rapidly.

7. In the art of heating, the passing of a stream of heated gasesthrough a heat radiating conduit, and the introduction there to atintervals of annular streams of cooler gases each in turn surroundingand moving forward more rapidly than the contents of the conduit at theplace where it is introduced, whereby uniformity of radiatingtemperature along the length of the conduit is approximated.

8. In the art of heating, the passing of a stream of heated gasesthrough a heat radiating conduit having successive sharp deflections ofdirection and the introduction thereto at places where a deflection hasoccurred of annular streams of cooler gases each in turn surrounding thecontents of the conduit at the place where it is introduced, wherebyuniformity of radiating temperature along the length of the conduit isapproximated.

9. method for approximating uniformity of temperature in the walls of atu bular conductor of heated gases, in which the said gases are directedand maintained in a central stream within the conduit and a coolergaseous medium is introduced as a tubular stream at higher velocitybetween the said central stream and the conduit walls, and keeps thegases of the central stream from direct contact with the walls.

10. Heating apparatus comprising a conduit of heat radiating material;means for introducing highly heated gases to the central portion of saidconduit with velocity in the direction of the length thereof; and meanswhereby an envelope of cooler gases is simultaneously introduced intothe conduit around said heated gases with greater velocity in the samedirection; whereby the said heated gases and cooler envelope moveparallel to each other as substantially separate bodies through theconduit and the high temperature gases are prevented from making directcontact with the conduit.

11. Heating apparatus for containing highly heated gases, comprising atubular conduit; an axial funnel through which the I said gases mayenter; an annular nozzle around said funnel through which cooler gasesmay enter, and suitable sources of energy for forcing in the said heatedgases at lower velocity and cooler gases at higher velocity the saidfunnel and nozzle being arranged to produce an envelope of said coolergases around the heated gases and thereby to prevent contact of thelatter with the walls of the conduit.

12. Heating apparatus comprising a heat radiating conduit having sharpdeflections of direction and adapted for containing a stream of highheated gases, said conduit being tubular and having a funnel at itsentrance end through which the heated gases may enter, an. annularnozzle around said funnel for introduction of cooler gases to form anenvelope in said conduit around said heated gases, and a funnel beyondeach sharp deflection of the conduit, through which the stream andenvelope may pass together, with an annular nozzle for the introductionof additional cooler gases to form a fresh envelope.

Signed at Boston, Massachusetts, this fourth day of March, 1920.

ALBERT J. LOEPSINGER.

